JPS60255990A - Method for recovering silver from photographic stabilizing solution - Google Patents

Abstract

PURPOSE:To recover high purity silver from a photographic stabilizing soln. by electrolysis with high electric current efficiency by using stainless steel or titanium steel as the material of a cathode as an electrode for electrolysis. CONSTITUTION:A photosensitive silver halide material is fixed and processed with the photographic stabilizing soln. without carrying out washing. The used stabilizing soln. is electrolyzed to recover silver. At this time, stainless steel or titanium steel is used as the material of the cathode as the electrode for electrolysis. Any electric conductor or semiconductor may be used as the material of an anode, but carbon or carbon fiber is preferably used.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for recovering silver from a photographic stabilizer as an alternative to water washing, and particularly to a method for recovering silver from a stabilizing solution that does not require a washing step following a desilvering step. Regarding how to.

[Prior art]

In conventional processing methods including a washing step, methods for recovering silver from fixing solution, bleach-fixing solution, washing water, etc. include electrolytic silver recovery method, reduction precipitation method, metal displacement method, ion exchange resin method, electrodialysis method, Silver sulfide precipitation, bacterial precipitation, radiolysis, and other methods are known to recover soluble silver salts from various processing solutions.

On the other hand, recently, for the purpose of environmental conservation, water resources, low cost, pollution, etc., a technology has been developed that directly performs stabilization treatment without washing with water after fixing or bleach-fixing.
No. 43, No. 57-132146, No. 58-14834
No. 58-14834, and the like.

In such stabilization treatment, a processing solution having fixing ability is introduced into the stabilizing solution, and therefore, it has become necessary to develop a means for recovering silver from the stabilizing solution.

The inventor of the present invention has conducted intensive research on means for recovering silver from a stabilizing solution, and as a result, it has been found that the composition of the stabilizing solution has specificity.

In other words, since the soluble silver ions in the stabilizing solution are only carried over from the previous solution, the number of soluble silver ions present is extremely low, and if washing is performed before stabilization treatment, the silver ions will be washed away by the washing. It was found that the liquid composition has specificity such that even the components are accumulated in the stable liquid.

Furthermore, it was found that there are the following differences compared to the fixer. That is, looking at the ratio of warts to ammonia water in the fixer and the ratio of hypo to ammonia water in the stabilizer, the ammonia concentration in the stabilizer is relatively high, and the chelate concentration in the stabilizer is relatively high. It was found that there are differences in that they are expensive, and that they also contain special ingredients such as anti-piping agents.

The present inventor has conducted further intensive research on methods for recovering silver from a stable solution containing the unique composition described above, and has discovered that the most effective means for recovering silver is an electrolytic method using a specific cathode. It has reached the point of completion.

[Purpose of the invention]

Therefore, a first object of the present invention is to provide a method for recovering silver from a photographic stabilizer as an alternative to water washing by an electrolytic silver recovery method with high current efficiency, and a second object of the present invention is to provide a method for recovering silver from a photographic stabilizer as an alternative to washing with water. The purpose is to provide a method for recovering silver from a water-washing alternative photographic stabilizer that can recover metallic silver, and the third purpose is to recover silver from a water-washing alternative photographic stabilizer using an electrolytic silver recovery device that has a cathode material that is stable for a long time with respect to the stabilizer. The objective is to provide a silver recovery method. Furthermore, a fourth object of the present invention is to provide a method for recovering a silver surface of a stabilizing solution as an alternative to water washing, in which the stabilizing solution can be reused.

[Summary of the invention]

The method for recovering silver from a photographic stabilizer according to the present invention is carried out by electrolyzing the photographic stabilizer in a waterless washing process in which a silver halide photographic light-sensitive material is treated with a photographic stabilizer without substantially washing with water after a fixing process. In the method for recovering silver from a photographic stabilizer, the cathode material of the electrolytic electrode is stainless steel or titanium steel.

[Structure of the invention]

The electrolytic means in the present invention is to perform electrolysis and recover silver using an electrolytic silver recovery device. An electrolytic silver recovery device basically has an electrolytic cell and both electrodes, a cathode and an anode made of a specific material, in the electrolytic cell, and by passing a direct current through the two electrodes, metallic silver is deposited on the cathode, The silver is recovered.

The electrolytic cell used in the present invention is preferably made of an insulating material that can be used for a long time or for repeated use, and synthetic resins such as polyvinyl chloride, polyvinyl methacrylate, polyethylene, polypropylene, and phenol formaldehyde resin are particularly preferably used. It will be done.

Stainless steel or titanium steel is used as the cathode material of the electrolytic electrode.

Stainless steel is an alloy whose main component is iron, and contains a small amount of chromium 11 to 30, nickel O to 37, molybdenum O to 4, titanium 0 to 1, and copper O to 3. It is. Specifically, the following stainless steels are specified by the Japanese Industrial Standards (JIS): 5 US 200 series to 400 series and 600 series (JIS G 4303 to
IS G 4313-G4315.1972), 5U
S-8TKS (JIS G3459-1968, JI
SG3463-1968, JISG3441-1
966), 5C8 (JIS G 5121-1969)
, D and Y 300-400 series (JIS Z 3z
2x-t96s, JIS Z 3321-1969)
, 5UH (JIS G 4311-1972, JrS
G4312-1972), 5CH (JIS G 51
22-1969) is used. Among these stainless steels, for example, 5u5200 series, 30% chromium, etc., containing at least 11% to 30% chromium and 3π to 20% nickel.
0 series and 600 series are preferably used, and more preferably at least 16 to 20% chromium and 10 to 16% nickel.
For example, 5US containing molybdenum 1.2 to 4.0
316, 316L, 316Ji, 316JIL, 317
is used.

Further, titanium steel refers to gold Jli whose main component is titanium (including alloys and mixtures with other metals), and the titanium content is preferably at least 50 or more, more preferably 90 or more, Particularly preferably, it is 99 or more.

The material for the anode may be any electrical conductor or semiconductor that does not dissolve in electrolysis or in a stabilizing solution and can withstand long-term use or repeated use, especially carbon (
(including graphite) and/or carbon fibers are preferably used.

The cathode and anode may have any shape such as a disk, cylinder, plate, grain, or fiber, but it is particularly preferable that the cathode is a cylinder and the anode is a combination of a cylinder and a fiber.

Stirring of the liquid in the tank is important, and stirring by liquid feeding and/or rotation of the cathode is preferred. In addition, the cathode and anode may be separated by a septum, and membrane materials include cow permeable membrane, stone M@, unglazed plate, thin glass, sintered glass, glass fiber, microporous synthetic polymer (for example, , polyvinyl chloride membrane, polystyrene membrane, polysulfone membrane, polyester membrane, polypropylene membrane, etc.) and ion exchange membranes.

Electrolytic conditions are not particularly limited, but the cathode potential is -0.40
~-0,55V, the anode potential is O ~ 0.20V (vs. saturation Carmel potential), that is, the potential between the electrodes is 0.40 ~ o, s
The range of ov (including potential due to solution resistance) is preferable.

Next, a recovery method of the present invention incorporating the above-described electrolyzer will be explained.

Although the silver recovery of the present invention is aimed at a water washing substitute stabilizing solution, the reason why silver is contained in such a stabilizing solution is that the silver component desilvered in the previous step of the stabilization treatment process is not recovered. Or, they are brought into the photographic material in rounded shapes that are not sufficiently recovered. Even in this case, if there is a means to discharge and recover the silver component from the system by washing with water before the stabilization treatment, the silver component brought into the stabilizing solution is not a subject of consideration. Since it is unique in that it eliminates washing with water, the silver content introduced is very low in concentration, but cannot be ignored.

Also, what is brought into the stabilizing solution is not only the silver component but also other fixing components, so of course the ammonia concentration in the fixing solution (versus warts) and the ammonia concentration in the stabilizing solution (versus - Warts) become extremely variable, and the ammonia concentration in the stabilizing solution becomes relatively high. It is clear that there are other differences in the composition of the chelating agent, anti-spill agent, etc., which will be described later.

Although it is thought that this change in composition, especially a change in ammonia concentration or a low concentration, may have caused the silver to be turned off, it was discovered that the means for recovering silver from the fixer solution could not be directly applied as a means for recovering silver. As a result of various studies, the present invention was discovered.

In the present invention, the fixing treatment of a silver halide photographic light-sensitive material is a treatment for the purpose of desilvering, specifically a treatment using a bleach-fixing bath or a fixing bath, etc.). The bleach used is not particularly limited, but
It is particularly effective when using an organic acid ferric complex salt, and is particularly effective when using a thiosulfate, although the fixing agent is not limited. It is more effective when using a fixing bath or a bleach-fixing bath containing thiosulfate.

In the present invention, water washing treatment is not performed before the post-fixing stabilization treatment, but the inclusion of treatments such as rinsing is not excluded. Furthermore, a draining bath containing a surfactant and formalin can be provided after the stabilization treatment.

The method of bringing the stabilizing solution of the present invention into contact with a photosensitive material is as follows: 1. It is preferable to immerse the photosensitive material in the solution in the same way as a general processing solution.
It may be applied to the emulsion surface of the photosensitive material, both sides of the transport leader, and the transport belt using a sponge, synthetic fiber cloth, etc.
Alternatively, it may be sprayed (by spray, etc.).

The stabilizer of the present invention preferably contains a chelating agent, and preferable chelating agents include organic carboxylic acid chelating agents, organic phosphoric acid chelating agents, polyhydroxy compounds, condensed phosphates, etc., and among them, preferable chelating agents include Agents include ethylenediamine diorthohydroxyphenylacetic acid, nitrilotriacetic acid, H)'Oxyethylenediaminetriacetic acid, cyclohexanediaminetetraacetic acid, ethylenediamine Tetrakis methylene phosphonic acid, nitrilotrimethylene phosphonic acid, 1
-Hydroxyetherithene-1,1'-diphosphonic acid, 1
．． 1-diphosphonoethane-2-carboxylic acid, 2-phosphonobutane-1,2,4-)licarboxylic acid, 1-hydroxy-1-phosphonopropane-1,2,3-1licarboxylic acid, catechol-3,5-disulfone Examples include tetrium pyrophosphate, sodium tetrapolyphosphate, and sodium hexametaphosphate, and 1-hydroxyethylidene-1°1'-biphosphonic acid and salts thereof are particularly preferred for the effects of the present invention. Addition amount is 1 stabilizer, jD
The range is preferably from 0.01 g to 100 g, more preferably from 0.1 g to 50 g.

(Preferable compounds to be added to the stabilizer of the present invention include pH adjusters such as acetic acid, sulfuric acid, hydrochloric acid, nitric acid, sulfanilic acid, potassium hydroxide, sodium hydroxide, ammonium hydroxide, sodium benzoate, Butyl hydroxybenzoate, antibiotic.

anti-pecking agents such as tehydroacetic acid, potassium sorbate, thiabendazole, ortho-phenylphenol, 5-chloro-2-methyl-4-isothiazolin-3-one, 2
-octyl-4-isothiazo1Jy-3-,one,1-
Preservatives such as 2-pentisothea/IJ-3-one, water-soluble metal salts, dispersants such as ethylene glycol, polyethylene glycol, and polyvinylpyrrolidone, and hardening agents such as hydrosulfite, dirosulfate, and formalin. , a fluorescent whitening agent, and the like.

The most effective of these compounds is...hydrosulfide),! I! Sulfates, etc., are effective when added before electrolysis.

The pH value of the stabilizer of the present invention is preferably adjusted to pH 0.1 to 10, preferably p) (2 to 9, y), and preferably U.
A suitable range is pH 6 to 8.5.

Recovery of electrolytic silver from the stabilizing solution of the present invention can be carried out from the stabilizing solution waste liquid and/or the stabilizing tank liquid, preferably from the stabilizing liquid waste liquid. Furthermore, when the stabilizer of the present invention is not reused, electrolytic silver recovery by mixing the fixer and bleach-fix solution is more efficient than recovering electrolytic silver from the fixer and bleach-fix solution alone. It's good to see the rise.

The silver to be recovered in the present invention mainly includes silver ions (including silver complexes), silver compounds, metallic silver, and the like. Although the silver concentration is not particularly limited, the effect of the present invention is remarkable in a low concentration range.

In addition, the recovery method of the present invention can be carried out in a batch type or a continuous type.The batch type is a method of replacing the electrolyte in which a certain amount of stable liquid is electrolyzed for a certain period of time, and the continuous type is a method in which the electrolytic solution is constantly replaced with a stable liquid in an electrolytic tank. This method supplies water and discharges overflow at the same time. In the present invention, a batch method is preferred.

In the present invention, the stabilization treatment tank is preferably a multi-stage tank, and the replenisher is replenished from the last stage tank and preferably uses a backflow system in which it sequentially overflows to the previous stage tank. The number of stabilization treatment tanks is 6.
The number of tanks or less is preferable, and the number of tanks or less is particularly preferable. Of course, a single monk may be used.Also, when the electrolytic silver recovery equipment is directly connected to the stabilization treatment tank,
It is desirable to connect directly to the first bath near the processing bath having fixing ability. In this case, it is effective to add the compound that releases sulfite ions, which is preferably used in the present invention, to the 141st bath and/or the 2nd bath, which is close to the processing bath having fixing ability.

When the stabilizer of the present invention is regenerated after electrolytic silver recovery, activated carbon,
The treatment may be performed using an ion exchange resin, electrodialysis, reverse osmosis, etc., and it is preferable to add a stabilizing liquid component as a regenerating agent.

〔Example〕

Example R of the present invention will be described below, but the present invention is not limited thereto.

Example-1 After printing color paper manufactured by Konishiroku Photo Industry Co., Ltd.,
Continuous replenishment processing was performed using an automatic developing machine. The treatment steps and composition of the treatment liquid at this time are as follows.

Standard treatment process [1] Color development 38°C 3 minutes 30 seconds [2] Bleach-fixing 33°C 1 minute 30 seconds [3] Stabilization treatment 25°C ~
30°C 3 minutes [4] Drying 75°C to 80°C approximately 2 minutes Processing solution composition <Color developer tank liquid><Color developer replenisher> Bleach-fix tank liquid> Bleach-fix replenisher A] Bleach-fix replenisher B〉 Stabilizer〉 Fill an automatic processor with the above color developer tank solution, bleach-fix tank solution, and stabilizer, and add the above color developer replenisher and bleach-fix replenisher every 3 minutes while processing the color paper. A running test was conducted while replenishing A, 8 and stable brightening solution through a metering cup. Refill amount is color paper-1
/F/3 as the amount of replenishment to the color developing tank for each
24 m, 251 Rt each of bleach-fixing replenishers A and B were replenished to the bleach-fix tank, and 250 st of stabilizing solution was replenished to the stabilization treatment bath.

In addition, the stabilization processing baths of the automatic WJ developing machine are the 11th to 3rd stabilizing baths in the direction of the flow of the photosensitive material, replenishment is performed from the final tank, and overflow from the final tank is allowed to flow into the previous stage. Furthermore, a multi-tank countercurrent system was adopted in which this overflow liquid also flows into the preceding tank.

Continuous processing was performed until the total replenishment amount of stabilizing solution became three times the capacity of the stabilizing tank.

Experiment-1 Further continuous processing was performed to collect the stabilizing solution overflow, and using a cylindrical electrolytic silver recovery device as shown in Figure 1, the material of the cathode cylinder 1 (cathode) was changed to aluminum, zinc, brass, steel, Nickel 3 on nickel chromium molybdenum steel
, chromium 3, molybdenum 0.6), carbon steel, stainless steel (JIs) 5US430, 5US
304, 5US316 and titanium steel (to 99,0) [
In each case, the voltage between the two electrodes was changed, and the cathode current density was set to 0.3 A/drr? After setting, electrolysis was performed for 80 minutes. The electrolysis is carried out by passing a current through the DC power source and rotating the central part by the drive motor. The amount of electrodeposited silver and amount of current for each material of the cathode were measured, and the current efficiency, which indicates the actual amount of electrodeposition compared to the theoretical amount of electrodeposition, was calculated and is shown in Table 1. In the figure, 2 is an anode, 3 is a tank cylinder, 4 is a drive inner cylinder, 5 is a large pulley, 6 is a belt, 7 is a drive motor, 8#/'i is a small pulley, 9i is a DC power supply section, 10 indicates the control L11#-1 float unit, 12 indicates the plassie carbon, 13 indicates the slip ring, 14 indicates the liquid supply pump, 15 indicates the drain pump, and 1B indicates the rubber elbow.

Experiment-2 Each electrode used in Experiment-1 was placed in the stabilizer overflow.
The specimens were immersed for several months and observed for corrosion, which is listed in Table 1.

on the table bow ] Note-1○...No corrosion.

Δ... Corrosion is observed.

X: Severe corrosion.

As is clear from Table 1, the material of the shaded scratches is aluminum.
In the case of using zinc, brass, steel, nickel chromium molybdenum steel, or carbon steel, the current efficiency is low, and it is unstable with respect to the stabilizing liquid and easily corroded, so that it cannot be put to practical use.

On the other hand, the one using stainless steel and titanium steel used in the present invention has a high current efficiency, is stable against stabilizing liquid, and is difficult to corrode, and has been found to be very effective.
In particular, 5US316 and titanium steel are preferred because of their durability against corrosion, and titanium steel is most preferred because of its high current efficiency and corrosion resistance, which makes it extremely effective. Furthermore, when we analyzed the purity of electrodeposited silver, we found that silver sulfide was generated in products other than stainless steel and titanium steel, and the purity was around 95, whereas in stainless steel and titanium steel, the silver content was over 99, which was extremely high. I liked it.

Example-2 The bleach-fix overflow discharged from the continuous processing of Example-1 was applied to the cathode material of the electrolytic silver recovery device shown in Figure 1.
When electrolysis was carried out using US316, the current efficiency was 14. Similarly, when a mixture of bleach-fix overflow and stabilizer overflow was electrolyzed, the current efficiency was 29. Therefore, silver recovery from the electrolytic silver recovery device Vi used in the present invention from the bleach-fix solution is small, and when a mixture of the stabilizer and bleach-fix solution is used, silver recovery from the stabilizer in Example-1 is difficult. It can be seen that the current efficiency is high as well, which is preferable.

Example 3 A continuous process was carried out using the following stabilizer formulation in place of the stabilizer formulation of Example 1, and the bleach-fix overflow and stabilizer overflow were collected in one tank and used as a sample.

<Stabilizing solution> To the above sample solution, 20 g of chelating agent 1 of Hato 1 to N115 shown in Table 2 was added, and the cathode IC8 shown in Fig. 1 was prepared.
The cathode current density is 0.5 k/dn by electrolytic silver recovery equipment using US316? Electrolysis was carried out until silver sulfide was generated on the cathode surface. -1~l@5
The current efficiency and purity of electrodeposited silver were measured and are listed in Table 2.

As is clear from Table 2, in the present invention, Ugly 2 to 5 to which a chelating agent is added are preferable to 11C to which no chelating agent is added, and Hato 3 to 5 are particularly preferable. It has been found that 1-hydroxyethylidene 1,1'-niphosphonic acid with Na5 is particularly preferred.

Comparative Example 1 As a comparison with the method of the present invention, an attempt was made to recover silver by bringing iron wool into contact with a stabilizing solution (ring precipitation method) as a silver recovery method other than electrolysis, but the silver recovery efficiency was low.

In addition, attempts were made to recover silver as silver sulfide by adding sodium polysulfide to the stabilizing solution (silver sulfide precipitation method).
Sedimentation was poor and silver recovery efficiency was low, which was unfavorable.

Example-4 In an experiment similar to Example-1, the first stabilization treatment tank
The electrolytic silver recovery device shown in Fig. 1 was directly connected to the tank, and a liquid supply pump was used to feed the stabilizing solution into the electrolytic tank from the first tank, and the overflow was directed back to the first tank. Cathode is titanium steel (99)
Made in Japan.

The amount of replenishment of the stabilizing liquid is 1/3 of the capacity of the first stable tank.The amount of color paper processed in one day is small, and the amount of replenishment is 1/10vrJ of the first tank! 1 Continuous processing of moving the W Kasumi-Koishi Arrival due to jealousy f: 1
After several months of testing, both silver recovery and photographic performance were good.

Next, the amount of supplementary light per day is 14th! When the treatment was carried out at a rate of 1/30, precipitation occurred in all the tanks, resulting in the precipitation adhering to the color vapor after treatment. In the same way, 0.2g of hydrosulfite was added per day to the first and second cases, and the same procedure was carried out. No precipitation occurred and the results were very good. It can be seen from the above that when the amount of treatment per day is small, the use of hydrosulfite in the present invention is extremely effective in suppressing the problem of precipitation.

In addition, since precipitation due to the above-mentioned small-volume treatment is likely to occur when the number of rows is 5111 or more, particularly in the 5i1 to 7111 rows, it has been found that stable rows of 4111 or less are preferable.

Example 5 Regarding the experiment in which titanium steel was used as the cathode material in Experiment 1 of Example 1, an anion exchange resin "Diaion WA-20" (Mitsubishi Kasei 81) was used after recovering electrolytic silver.
After contacting the solution, the stabilizer composition of Example-1 was added and reused as a replenisher. As a result, the photographic performance of the color paper was extremely good without any problems.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an electrolytic silver recovery apparatus preferably used in the present invention. In the figure, 1 indicates a cathode cylinder (cathode) and a 2-wire carbon (lit pole), respectively. Patent applicant: Agent for Konishiroku Photo Industry Co., Ltd. Patent attorney: Akira Saka (and one other person) Procedural amendment (voluntary) August 30, 1985 Commissioner of the Patent Office Mr. Michibu Uga Country 1 Indication of the case 1982 Patent Application No. 110944 2 Name of the invention Method for recovering silver from photographic stabilizer 3 Relationship to the case of the person making the amendment Name of applicant (127) Roku Konishi Photo Industry Co., Ltd. 4 Agent
160 Address No. 2, 10-11, Nishi-Shinjuku 7-chome, Shinjuku-ku, Tokyo, 5th floor, Jushiko 5 Date of notice of reasons for refusal Voluntary action 6 Number of inventions increased by amendment 7 Contents of the amendment subject to the amendment (specific Application No. 59-110844) The specification is amended as follows. 1 Add the following between lines 9 and 10 on page 2. Furthermore, as described in JP-A-58-134636, the amount of replenishment of the stabilizing solution that does not require water washing is approximately 25 mjL to 2.5 mjL per rn' of photographic light-sensitive material, but preferably 50 mjL. ~iM, more preferably 5h
It is supplemented with fL~200■ sentences. 2 Page 7, line 13 ni r-0,40~-0,55V, J
The voltage is corrected as r −0,40 to −0,65V. 3 On page 7, line 13, the phrase ``There are condensed phosphates, etc.,'' should be corrected to ``There is condensed phosphorus, J.'' 4 On page 11, line 13, the phrase ``dehydroacetic acid'' should be changed to ``dehydroacetic acid.'' Acetic acid”. 5 Page 10, lines 15-16, page 11, lines 3-4, page 15, line 8, page 16, line 6, page 24, Table-2, N
In the chelating agent column of 015 and the bottom line of page 24 to the first line of page 25, "l-hydroxyethylidene-1,1'-diphosphonic acid" is replaced with "1-hydroxyethylidene-1,1'-diphosphonic acid".
1-diphosphonic acid" respectively. that's all

Claims (1)

[Claims] In a method for recovering silver from a photographic stabilizer, in which silver is recovered by electrolyzing the photographic stabilizer in an anhydrous washing process in which a silver halide photographic light-sensitive material is treated with a photographic stabilizer without substantially washing with water after a fixing process, the electrolytic A method for recovering silver from a photographic stabilizer, characterized in that the cathode material of the electrode is stainless steel or titanium steel.